Municipal, well or lake water is commonly used to make the initial ice sheet of an ice rink and for maintenance of the ice. Such water contains mineral salts, dissolved solids and other impurities. The higher the concentration of these impurities, the higher the "specific conductance" (ie. micromhos/cm) of the water. Using water having a high level of impurities, and accordingly, a high specific conductance (ie. 200-800 micromhos/cm), results in poor ice quality and increased energy and operating costs for the following reasons.
As the ice rink water freezes, the water port ion freezes first pushing dissolved solids into the remaining liquid portion where salts and other impurities concentrate. This final portion eventually freezes, but at the surface of the ice sheet, where at the presence of a high concentration of impurities causes the ice surface to be soft, shaley, and opaque in appearance.
Based on a municipal water supply having a specific conductance of 350 micromhos/cm, a typical core sample of an ice sheet would reveal the bottom portion (ie. concrete or sand interface) as being relatively pure (ie. 180 micromhos/cm), while the surface of the ice could have a specific conductance as high as 700 micromhos/cm. Additionally, the specific conductance of the ice surface will increase over time, through the inherent processes of evaporation and sublimation, further deteriorating the quality of the ice surface.
During the maintenance of the ice, an ice resurfacer (ie. Samboni', Olympia', etc.) is used to shave the ice to remove slush, snow, and dirt from the surface of the ice. The resurfacer then floods the surface of the ice with fresh water thereby applying a fresh surface layer of ice. The shavings picked up by the resurfacer from the ice's surface are stored in a snow tank within the resurfacer. After the resurfacing operation, the shavings in the snow tank are dumped into an ice pit to melt and the resulting water is disposed of by drainage into the municipality's sewage system.
The amount of energy and water used for ice making and maintenance is substantial. For example, a rink must heat about 120 gallons of water to 150 degrees Fahrenheit every time the ice of the rink is flooded. Not only does this require energy to heat the water (about 90,000 Btu/flood), but the warm water creates a refrigeration load of about 260,000 Btu/flood (ASHRAE, Journal, April 1992, "Modernizing and Retrofitting Ice Skating Rinks", Russell Blades).
In terms of water consumption, ice making and maintenance will require about 800,000 gallons of water per year for an average sized rink. Additionally, to help speed up the melting of the ice in the ice pit, many ice rink operators apply hot water to the pit from a hose. This practice not only wastes water, but energy as well.
For ice rinks that use cooling towers or evaporative condensers and compressors, annual water usage for this equipment is typically an additional 2,500,000 gallons.
There is, therefore, a need for an improved ice rink maintenance process which reduces water and energy consumption while improving the quality of the ice surface.